Archive for April, 2017


An unpatched vulnerability in the Magento e-commerce platform could allow hackers to upload and execute malicious code on web servers that host online shops.

 

The flaw was discovered by researchers from security consultancy DefenseCode and is located in a feature that retrieves preview images for videos hosted on Vimeo. Such videos can be added to product listings in Magento.

 

The DefenseCode researchers determined that if the image URL points to a different file, for example a PHP script, Magento will download the file in order to validate it. If the file is not an image, the platform will return a “Disallowed file type” error, but won’t actually remove it from the server.

 

An attacker with access to exploit this flaw could achieve remote code execution by first tricking Magento to download an .htaccess configuration file that enables PHP execution inside the download directory and then downloading the malicious PHP file itself.

 

Once on the server, the PHP script can act as a backdoor and can be accessed from an external location by pointing the browser to it. For example, attackers could use it to browse the server directories and read the database password from Magento’s configuration file. This can expose customer information stored in the database, which in the case of online shops, can be very sensitive.

 

The only limitation is that this vulnerability cannot be exploited directly because the video-linking functionality requires authentication. This means attackers need to have access to an account on the targeted website, but this can be a lower-privileged user and not necessarily an administrator.

 

The authentication obstacle can also be easily overcome if the website doesn’t have the “Add Secret Key to URLs” option turned on. This option is intended to prevent cross-site request forgery (CSRF) attacks and is enabled by default.

 

CSRF is an attack technique that involves forcing a user’s browser to perform an unauthorized request on a website when visiting a different one.

 

“The attack can be constructed as simple as <img src=… in an email or a public message board, which will automatically trigger the arbitrary file upload if a user is currently logged into Magento,” the DefenseCode researchers said in an advisory. “An attacker can also entice the user to open a CSRF link using social engineering.”

 

This means that by simply clicking on a link in an email or by visiting a specifically crafted web page, users who have active Magento sessions in their browser might have their accounts abused to compromise websites.

 

The DefenseCode researchers claim that they’ve reported these issues to the Magento developers back in November, but received no information regarding patching plans since then.

 

Several versions of the Magento Community Edition (CE) have been released since November, the most recent one being 2.1.6 on Tuesday. According to DefenseCode, all Magento CE versions continue to be vulnerable, which is what prompted them to go public about the flaw.

 

“We have been actively investigating the root cause of the reported issue and are not aware of any attacks in the wild,” Magento, the company that oversees development of the e-commerce platform, said in an emailed statement. “We will be addressing the issue in our next patch release and continue to consistently work to improve our assurance processes.”

“All users are strongly advised to enforce the use of ‘Add Secret Key to URLs’ which mitigates the CSRF attack vector,” the DefenseCode researchers said. “To prevent remote code execution through arbitrary file upload the server should be configured to disallow .htaccess files in affected directories.”

 

Magento is used by over 250,000 online retailers, making it an attractive target for hackers. Last year, researchers found thousands of Magento-based online shops that had been compromised and infected with malicious code that skimmed payment card details.

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Microsoft released its monthly security-patch bundle Tuesday, fixing 45 unique vulnerabilities, three of which are publicly known and targeted by hackers.

The top priority this month should be given to the Microsoft Office security update because one of the fixed flaws has been actively exploited by attackers since January to infect computers with malware. Over the past few days this vulnerability, tracked as CVE-2017-0199, has seen widespread exploitation.

The CVE-2017-0199 vulnerability can be exploited through maliciously crafted RTF (Rich Text Format) documents when such documents are opened with either Microsoft Word or WordPad. Because WordPad is bundled with Windows by default, a patch for this flaw is also included in the security updates for Windows.
According to security vendor Qualys, the next priority should go to the updates for Microsoft’s Internet Explorer and Edge browsers. These update address several remote code execution vulnerabilities.

One flaw patched in IE allows attackers to bypass the cross-domain policies enforced by the browser. The flaw makes it possible to take information from one domain and inject it into another, violating an important security barrier.

Microsoft’s notes for this vulnerability mention that it has already been exploited in the wild, but don’t include other details about the attacks.

Critical vulnerabilities have also been patched in Hyper-V, Microsoft’s virtualization hypervisor that’s included in Windows Server 2008, 2012 and 2016, as well as in Windows 8.1 and 10. These vulnerabilities can allow applications running inside a guest operating system to escape the virtual machine and execute malicious code on the host OS.

Finally, a remote code execution vulnerability has been fixed in the Microsoft .NET Framework. This flaw potentially can be exploited by attackers to take complete control of a system running a vulnerable deployment of the framework.

Microsoft has also released a defense-in-depth update for Microsoft Office that disables the Encapsulated PostScript (EPS) filter by default. That’s because the company is aware of limited, targeted attacks that try to take advantage of an unpatched vulnerability in this filter.

The Microsoft updates also include third-party critical patches for Flash Player, which is bundled with Internet Explorer 11 and Edge.

This Patch Tuesday bundle is also notable because it marks the end of support for Windows Vista, which will no longer receive security updates after this round of patches.

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